This invention relates to a canister for reducing the loss of vaporizing fuel.
A canister having a fuel vapor inlet port and a purge port on one side of a chamber accommodating activated carbon and an atmospheric air port on the other side has been conventionally used as an apparatus for reducing fuel vapor loss which contains activated carbon for adsorbing fuel vapor generated in such portions of a fuel system as a fuel tank during the shut-down state of an engine and which supplies the adsorbed fuel vapor to the engine when the operation of the engine recommences.
It is important for this type of canister to diffuse the fuel vapor which is to be adsorbed over the entire region of an activated carbon chamber in order to increase the efficiency of adsorption and separate the adsorbed fuel vapor from the adsorbent as completely as possible so as to increase the efficiency of readsorption.
In this respect, means for diffusing fuel vapor by using a baffle plate having apertures disposed in a fuel vapor passage have been proposed, as disclosed in Japanese Utility Model Examined Publication No. 9077/1984 and Japanese Utility Model Unexamined Publication No. 12395/1982.
On the other hand, means for separating adsorbed fuel from an adsorbent and having a suitable gap between the adsorbent layers and the atmospheric air port to ensure that the atmospheric air introduced from the atmospheric air port flows through this gap into the adsorbent layers have been previously proposed, as disclosed in Japanese Utility Model Examined Publication No. 33062/1972 and Japanese Utility Model Unexamined Publication No. 123953/1982.
It is an object of the present invention to improve the conventional type of such a canister with respect to the efficiency of fuel vapor adsorption by an adsorbent and the efficiency of purging from the adsorbent. To this end, the present invention provides a canister comprising a first deflector for improving the diffusion of fuel vapor by effecting swirling movement of the vapor flowing into the canister, and a second deflector for distributing throughout the canister the air which flows toward the canister for purging the vapor.
Other and further objects, features and advantages of the invention will appear more fully from the following description.